Matt Cutts stated in a video this week that adding a large number of page to your website all at once may not be a good idea. If the number of pages on your website increases suddenly it will alert search engines to investigate your site for spam.
If your content is legitimate then it won’t matter either way but it is better to add pages gradually so it will look more natural.
Bing has been testing a new results page that only has 5 websites returned on the first page of a query. Bing has been trying different result pages to see how users respond to different SERPs as a way to compete with Google.
A Google search from a mobile device will now offer sub site links to users just as they would appear in a search on a desktop. The new mobile feature gives users the opportunity to go directly to the page they ant to on a website instead of having to navigate to the home page first.